Blade sharpener



April 18, 1939. G. HAMMOND BLADE SHARPENER Filed Oct. 29, 1935 Patented Apr. 18, 1939 UNITED STATES PATENT OFFICE BLADE SHARPENER. Grant Hammond, Hamden, Conn. Application October 29, 1935, Serial No. 47,292

3 Claims.

My invention relates to the class of devices employed for creating a sharp edge on various devices more particularly on skates, lawn mowers, and the like, and an object of my invention, among others, is the production of a sharpener which may be used by the ordinary individual to create an edge at an angle most efficient for any particular device thereby producing a sharpener which is particularly simple in construction and most efiicient in operation.

One form of a sharpener embodying my invention and in the construction and use of which the objects herein set out, as well as others, may be attained is illustrated in the accompanying drawing in which- Figure 1 is a side view of my improved sharpener illustrating its manner of use.

Figure 2 is an end view of the same.

Figure 3 is a bottom view.

Figure 4 is an isometric perspective view.

Figure 5 is an isometric perspective view of the bottom of the device with the guides removed.

Figure 6 is a view in section on a plane denoted by the dotted line 6-6 of Fig. 3.

Figure 7 is a view in section on a plane denoted by the dotted line 1-l of Fig. 3.

Figure 8 is a detail view in cross section showing a different form of sharpening blade from that shown in the other figures.

In the accompanying drawing the numeral Ill denotes the block or handle of my improved sharpener which may be composed of any suitable material, preferably wood of a harder quality. A recess l l is formed in the bottom and prefera- 35 bly fiat face of the block and a base plate [2 is fitted into said recess and secured therein in any suitable manner as by means of screws. A boss 13 is extended across the plate at substantially its lengthwise center and a groove I4 is formed 40 in the boss extending lengthwise thereacross. This base is of curved shape as shown in Fig. 5 to form a seat for a sharpening blade.

A latch I5 is pivotally mounted in said groove as by means of a pin [6 extending across the 5 groove, said latch having a stop lug H at one end and a retaining lug l8 at its opposite end, this latter mentioned end having a thumb piece l9 by means of which the latch may be operated. The edge of the latch between said lugs is pref- 50 erably shaped to fit the form of a sharpener piece 20.

This sharpener piece in the form illustrated in Figures 1 to "I is of curved shape to fit and rest upon said boss and has a sharpening surface 55 2| on its outer face. This piece may be formed of any suitable hardened metal as nitrided nitralloy steel and the fine ribs and grooves are formed across the piece extending preferably in a diagonal direction, as shown in Fig. 3 of the drawing.

Guides 22 are adjustably secured to the base plate as by means of screws 23 projecting through slots 24 in foot parts at the ends of the guides, this fastening means being for the purpose of adjustably mounting the guides so that a blade being sharpened may make contact with the sharpener piece across the center of the arc, the crosswise center of said piece being located exactly on the radius of said arc. These guides are recessed as at 25 to receive the boss l3 and the sharpener piece 20 therein.

In the sharpening of blades for skates expert skaters prefer a blade the edge of which is concaved to a slight-extent and it is essential that this curve shall be on the arc of a circle the radius of which is at the center of the curve of the recess. This ensures that the opposite sharpened corners of the blades will lie in the same horizontal plane parallel with the plane of the foot supporting part of the skate.

The methods of sharpening skates at the present time do not ensure this accuracy as to the relative positions of the opposite sharpened corners of the blades and skaters therefore, particularly those engaged in the game of hockey, are obliged to use skates for a brief period in order to accustom themselves to the positions of the sharpened corners. With my improved device these sharpened corners are always in the same position and this testing of the blades and aocustoming ones self to the use thereof are not required, as in each instance the sharpened corners of the blades will be in exactly the same positions after each sharpening operation. Further than this, expert work is not required in order to sharpen a blade as the act may be accomplished by anyone.

When it is required to remove the sharpening piece pressure of the thumb nail against the thumb piece I9 will cause the lug 18 to be de pressed so that the piece may be readily removed, and a contrary action will suffice to enable the piece to be readily replaced.

That form of the device shown in Fig. 8 is particularly for the purpose of grinding a blade, as a lawn mower blade, with a beveled edge. The structure is the same as hereinbefore described with the exception that the latch I5 is formed with an edge to receive the sharpening blade 26, said edge comprising two parts 10- cated at an angle each to the other. The blade in this instance is flat and is obliquely located with respect to the guides 22 so that a blade, as a lawn mower blade, being passed through the space between the guides will be given the proper bevel to ensure the best result in cutting action, and this angle of bevel of the blade will always be maintained after each sharpening operation.

In accordance with the provisions of the patent statutes I have described the principles of operation of my invention, together with the device which I now consider to represent the best embodiment thereof; but I desire to have it understood that the device shown is only illustrative and that the invention may be carried out by other means and applied to uses other than those above set out.

I claim:

1. A blade sharpener including a supporting base having a curved seat and a groove in said seat, a sharpener piece resting on said seat, a latch located in said groove in said seat and having means for unobstructedly removably retaining said piece on said seat, and guides spaced apart to provide a groove to receive a blade to be sharpened and for relative sliding movement as between said piece and blade.

2. A blade sharpener including a supporting base having a seat for a sharpener piece, said seat being divided to form a groove, a sharpener piece resting on said. seat, a latch pivotally mounted in said groove in said seat and extending underneath said sharpener piece and having a retaining lug at one end and a stop lug at the opposite end to removably secure said sharpener piece in place, and guides spaced apart to provide a groove to receive a blade to be sharpened and for relative sliding movement as between said piece and blade.

3. A blade sharpener including a supporting base, there being a divided raised boss on said base forming a groove and having a curved surface to provide a curved seat, guides adjustably secured to said base and having recesses in their under surfaces bridging said boss, a latch located in said groove in said boss and extending through notches in the under surfaces of said guides, a thin sharpening blade resting on said boss and extending into the recesses of said guides, and means on said latch for unobstructedly retaining said sharpening blade in place.

GRANT HAMMOND. 

